Lifting jack



NQV. 24, 1931. J, KLEE ET AL 1,833,082

LIFTING JACK Filed oct. 19, 1926 Patented Nov. 24, 1931 UNITED l"STATES JOSEPH KLEE AND ALFONS SCHNEIDER, OFYMUNI'CH, GERMANY LIFTING JACK .Application ledcto'ber 19, 1926, 'Serial No. .1142,679, and in Germany '0ctober21, 1925.

Our invention relates tolifting jacks 'for :motorcars and the like and it is an object of our invention to provide a jack of the kind described which is so designed as to be able to operate permanently under unfavourable conditions, `for instance, in water or in miry ground. T Othis end we so arrange the worm gear or other part the rotation of which is `changed into parallel motion of a plunger or w the like that it closes tightly the casing of the jack and imparts not only parallel but .also rotarymotion to the `plunger sothat any impurities and the likel are stripped `from the plunger bythe combined rotary and `par- 'Jl allel motion, and we so arrange the :means for operating the plunger, for instance, the

worm fgear, that the worm gear isentirely relieved `from thrust and the lstress exerted von the `gear results exclusively `from tooth reaction.

.Inthedrawings aiiixed to this specification and forming part thereof a lifting jack embodyingfour invention is `illustrated diagrammatically by way of example.

In the drawings Fig. l is a longitudinall section along the axis of the jack,

Fig. 2 is a corresponding section illustrat ing its plunger separately,

Figs. 3, 4 and 5 are sections on the corresponding lines of Fig. 2,

Fig. 6 is an elevation, and

Fig. 7 is an end elevation of a control rod inserted in the jack,

Fig. 8 is an end elevation, and

Fig. 9 is a side elevation of the boss of the worm gear for rotating the plunger, with the rim broken away.

Referring now to the drawings, b is the i0 tubular casing of the jack, and a is a threaded spindle which is arranged concentrically in the tube and secured therein at one end by a boss al which is screwed into the tube and held against rotation by a pin 0. Z is a 45 plunger which is threaded at one end and seated on the spindle a. Its threaded end eX- tends as far as d the remaining portion of the plunger being Without a thread on the inside but fitting exactly the crest of the spindle threads. On the outside, the plunger is shaped to aprismatic section d?, for uinstance octagonal, as shown in Fig.4.

fis a worm gear the boss f1 ofwhich is seated on the octagonal portion cl2 of the plunger d. n is a worm which meshes with the vwormgear f', f2 Lis a packing and wiping ring Von the yplunger d which abuts against the boss 'of the worm gear f at its outer end. e is a casing whichis secured {air-tightlyon the tube l) Yand adapted to receive the means for rotating the worm gear, notshown. It will be understood that instead of Worm gearing, any other suitable means might be provided for imparting rotation to the plunger al. The boss f1 of the worm gear fis cylindrical-on the outside so as'to form a continuation of the tubular casing and `is abutted at one end against the tubularcasing. The casing c .is tanged i'or the reception of the tubular casing b at one end, and at its other end it is abutted against the body ofthefgear f Vbymeansot a re-bent collar e1 which makes air-tight connection at the boss and `the body7 of the worm gear.

When the `gear f is rotated lthe plunger d will rotate -with it andat'the same time will 'be displaced axially in the octagonal cavity o'f the boss f1. Penetration of water or im'- purities of any kind to the working .parts of the jack are prevented by the tight-fit off the boss 7'El on the prismaticportion of Athe 'plunger and Yby the casing e which surrounds the worm v gear f. y p

The rotation of the plunger with respect to the objectV to be liftedis permitted by a 'rotatable head which is secured on the outer end (Z3 ofthe plu-nger 0l. The end may be tapered as shown, -or cylindrical and proer la engaging a circling groove in the plunger d.. If required, the cap may be re-bent 'from the washer 7L and provided with a flange ,(/1 at its outer end. The thrust of the plunger is transferred to the 'cap g by a spherical thrust bearing z" i2 in the end cl3 of the plungerf K v if it is desired to apply the jack to -i-nclined faces a rubber cushion inserted -in the cap g which may consist of a comparatively hard part 701 at the centre and an annular part 7a2 surrounding thel central part 71:1. Obviously the cushion may be combined from any number of parts which may be arranged as desired, or it may consist of a r. rangement is constituted by the fact that the thrust of the jack is exerted on a single thrust bearing and the Worm gear 7 is entirely relieved from thrust so that the only forces acting thereon are constituted by the tooth reaction. Another important advantage is due to the arrangement of the Worm gear f which is adapted to rock freely about a stationary spindle and a reciprocating prismatie plunger' which eliminates the necessity of splining and correspondingreakening of the parts so that the amount of inaterial required is a minimum,

All Working parts of the jack and particularly the screw spindle a are encased by airtight means as described, and protected from access of impurities and the like in any relative position. The boss fl which, as mentioned. is tightly seated on the prismatic portion Z2 of the plunger7 acts as a stripper for removing impurities from the plunger when the latter is retracted.

In some cases. for instance When the jack is used for lifting carriages 0r for tipping7 it is necessary to provide an automatic control for its drive. In such cases a rod Z is inserted air-tightly in an axial bore of the spindle a and proiects from the boss a1. Its other end is provided with a disk m which fits exactly the bore of the plunger d. When the plunger (Z has been moved to the end of its stroke the shoulder (Z1 of its threaded portion will engage the disk m as shown in dotted lines in Fig. 2 and displace the rod Z axially. This displacement is transmitted to a control of any suitable tvpe which is preferably operated electrically. On the return motion of the plunger the block i of the bearingin the hollow end d3 will return the rod Z to its initial position.

This air-tight arrangement of the rod Z nuthin the jack and the stationary spindle a 1s a result of the rocking arrangement of the Worm gear f which enables the entire thrust of the jack to be distributed concentrically to the disk m and the rod Z. l

We Wish it to be understood that We do not desire to be limited to the exact details ot construction shown and described for obl vlous modifications will occur to a person skilled in the art.

We claim 1. A lifting jack comprising a base, a threaded spindle on said base, a tubular plunger on said spindle having a threaded part adapted to engage the thread of said l plunger on said spindle having a threaded part adapted to engage the thread of said spindle, a prismatic seat on the outside of said plunger, a casing secured to said base and surrounding the lower part of said plunger so as to guide it, a Wheel tightly f1tting i Cl prismatic seat and adapted to rotate with respect to said casing, means for rotating said Wheel, and a guard surrounding it.

3. A lifting jack comprising a base, a threaded spindle on said base, a tubular plunger on said spindle having a threaded part adapted to engage the thread of said spindle, a casing secured to said base so as to surround and guide said plunger, a resilient cushion at the outer end of said plunger, two members having spherical surfaces forming a thrust bearing intermediate said cushion and said plunger, a cap having an inner Wall surrounding said thrust bea-ring and an outer Wall enclosing said resilient cushion, and means for imparting rotary motion to said plunger.

In testimony whereof We affix our signatures.

JOSEPH KLEE. ALFONS SCHNEIDER.

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